Conventional human-powered bicycles are usually driven by a drivetrain system which was developed to transmit power from riders to drive wheels by a variety of methods. Most bicycle drivetrain systems incorporate a freewheel to allow coasting.
The simpler bicycle drivetrain system consists essentially of a single chainring on the right side of the bicycle; a chain; a pair of pedals on either sides and a sprocket on the rear wheel. The system basically converts the reciprocating motion of the rider's legs into rotational motion of the chainring, which subsequently drives the chain which in turn drives the rear wheel. More complicated systems may consist of more than one chainrings attached to the crank set to which the pedals are attached. The chainring is connected to the bicycle frame at the bottom bracket, and to the rear sprocket, cassette or freewheel via the chain. More sophisticated bicycles also include a cogset, a derailleur gears, hub gears, gear case and other parts to enhance efficiency of the bicycle.
Conventional drivetrain systems, while driven by pedals on both sides of the bicycle, primarily only utilize a chainring on one side; usually the right side of the bicycle. Both pedals are connected at the center of the chainring(s) by their respective crank arms coupled to the axle or bottom bracket spindle. There are a variety of methods used to attach the crank arms to the bottom bracket spindle including wedge-shaped pins or cotters, square tapered spindles, hexagonal tapered spindles, and splined bottom bracket spindles.
The present invention is a double chainring drivetrain system which has two identical chainring drivetrains on both sides of a bicycle; working simultaneously and in-sync. It is believed that the present invention can increase the efficiency of bicycles by having two identical chainring drive train.